| 2 | t | × | 2 | t | + | ( | 25 | − | t | ) | ( | 25 | − | t | ) | = | 25 | × | 25 |
| 方程左边 = | 4 | t | t | + | ( | 25 | − | t | ) | ( | 25 | − | t | ) |
| 4 | t | t | + | ( | 25 | − | t | ) | ( | 25 | − | t | ) | = | 25 | × | 25 |
| 方程左边 = | 4 | t | t | + | 25 | ( | 25 | − | t | ) | − | t | ( | 25 | − | t | ) |
| = | 4 | t | t | + | 25 | × | 25 | − | 25 | t | − | t | ( | 25 | − | t | ) |
| = | 4 | t | t | + | 625 | − | 25 | t | − | t | ( | 25 | − | t | ) |
| = | 4 | t | t | + | 625 | − | 25 | t | − | t | × | 25 | + | t | t |
| = | 4 | t | t | + | 625 | − | 50 | t | + | t | t |
| 4 | t | t | + | 625 | − | 50 | t | + | t | t | = | 25 | × | 25 |
| 方程右边 = | 625 |
| 4 | t | t | + | 625 | − | 50 | t | + | t | t | = | 625 |